A wireless communication device, such as a mobile phone device or a smart phone, may include two or more Subscriber Identity Modules (SIMs). Each SIM may correspond to at least one subscription via a Radio Access Technology (RAT). Such a wireless communication device may be a multi-SIM wireless communication device. In a Multi-SIM-Multi-Active (MSMA) wireless communication device, all SIMs may be active at the same time. In a Multi-SIM-Multi-Standby (MSMS) wireless communication device, if any one SIM is active, then the rest of the SIM(s) may be in a standby mode. The RATs may include, but are not limited to, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA) (particularly, Evolution-Data Optimized (EVDO)), Universal Mobile Telecommunications Systems (UMTS) (particularly, Time Division Synchronous CDMA (TD-SCDMA or TDS) Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), evolved Multimedia Broadcast Multicast Services (eMBMS), High-Speed Downlink Packet Access (HSDPA), and the like), Global System for Mobile Communications (GSM), Code Division Multiple Access 1× Radio Transmission Technology (1×), General Packet Radio Service (GPRS), Wi-Fi, Personal Communications Service (PCS), and other protocols that may be used in a wireless communications network or a data communications network.
A network (e.g., a WCDMA network) can configure various carrier information with respect to a wireless communication device through Radio Resource Control (RRC) layer signaling. Carrier options such as activating or deactivating a secondary cell can be configured through Layer 1 (L1) signaling, also known as Physical Layer signaling. An activation/deactivation order (e.g., a High-Speed Shared Control Channel (HS-SCCH) order) can be used by the network to dynamically enable or disable the secondary cell based on resource needs of the wireless communication device and current radio resource status (e.g., congestion status) of the network. The HS-SCCH order mechanism can be implemented to configure the secondary cell settings on the wireless communication device more rapidly than RRC layer signaling, which spans over tens of milliseconds.
Typically, the network sends a HS-SCCH order to a wireless communication device for configuring the secondary cell settings. The wireless communication device will send an Acknowledgement signal (ACK) or Negative Acknowledgement signal (NACK) in uplink to the network to indicate status of the HS-SCCH order. If the network does not receive any response from the wireless communication device, the network will retransmit the HS-SCCH order. If the network fails to receive any response corresponding to the retransmission(s) from the wireless communication device, the network will trigger RRC-level signaling for activating or deactivating the secondary cell configurations. The HS-SCCH order decoding can be highly reliably, and probability of successful Layer 1 signaling procedure with respect to HS-SCCH can approximate 100%. Therefore, due to the high reliability at Layer 1, the network generally assumes successful completion of the HS-SCCH order after the transmission/retransmission(s), and proceeds with target configurations of the HS-SCCH order on the network-side, even with the wireless communication device engaged in Discontinuous Transmission (DTX).
On the other hand, a multi-SIM wireless communication device having two or more subscriptions employs tune-away mechanisms for sharing a common Radio Frequency (RF) resource. That is, the RF resource can be tuned away from a first subscription to a second subscription for activities of the second subscription while suspending any activities of the first subscription, creating a tune-away gap with respect to the first subscription. The transmission/retransmission(s) of the HS-SCCH order that collide (e.g., overlap in time) with a tune-away gap spanning 50 ms to 100 ms can be lost, resulting in Layer 1 procedure failure. That is, the wireless communication device is not informed of the target configurations contained in the HS-SCCH order due to the tune-away gap.
Accordingly, given that the network proceeds with the target configurations corresponding to the HS-SCCH order and that the wireless communication device fails to receive the HS-SCCH order, a mismatch or disconnect between the network and the wireless communication device can result for the downlink channel configuration, thus negatively impacting the High-Speed Dedicated Physical Control Channel (HS-DPCCH) encoding in uplink. The network, in turn, would fail to decode the HS-DPCCH properly, resulting in failure to acquire Channel Quality Indicator (CQI) from the wireless communication device. The CQI is a measurement of quality of a communication link between the wireless communication device and the network. The failure is caused by the fact that different Reed-Muller tables are used for encoding for a single CQI and dual CQI. When an inappropriate Reed-Muller table is used, incompatible codewords are employed.
Subsequently, the network may stop scheduling downlink data completely because the wireless communication device may continue to retransmit Protocol Data Units (PDUs) in uplink until Radio Link Control (RLC) resets given that ACK on the High-Speed Physical Downlink Shared Channel (HS-PDSCH) is not being received by the wireless communication device. The ACK for uplink PDUs is being mapped to HS-PDSCH. At any rate, the wireless communication device unnecessarily consumes a considerable amount of energy by remaining in the connected state without actually transmitting and/or receiving data. The low throughput can negatively impact user experience due to page connection timeouts, slow buffering of videos, and/or the like.
The network can also misinterpret the CQI report, treating a high CQI report as a low CQI report, vice versa. For instance, while the wireless communication device remains in a connected state, the network can reduce scheduling for the wireless communication device as the network treats a high CQI report as a low CQI report, thus drastically reducing throughput. On the other hand, the network scheduling high Transport Block Size (TBS) for the wireless communication device as the network treats a low CQI report as a high CQI report, thus causing continuous decoding failure and Radio Link (RL) failures as well as RLC resets. The decoding failures, RL failures, and RLC resets can negatively impact user experience.